Thin Film Lithium Niobate Optical Waveguides for Integrated Optics.

Highly oriented polycrystalline thin films of lithium niobate on (012), (100), and (110) sapphire single crystal substrates, (111) silicon and SiO_2 /(100)Si wafers were grown by magnetron rf sputtering and metallo-organic decomposition techniques. A novel technique of photo-induced metallo-organic decomposition (PIMOD) is proposed and implemented to eliminate inter -diffusion and cracking which are commonly observed in MOD -derived films. Results of XRD, TEM, and ion beam spectrometry confirm that highly oriented, polycrystalline, stoichiometric lithium niobate thin films have been successfully grown on a variety of substrates. Prism coupling has been used to excite the guided modes in the optical thin film waveguides. The optical and electrooptic properties, including the refractive index, propagation losses, and electrooptic coefficient, were investigated. Finally, an electrooptic phase modulator was implemented.